Toyota Supra 1990 Manual page 221

EFI SYSTEM - Troubleshooting with Volt/Ohmmeter
(7M-GEl
FI-47
California vehicles only
ECU
Voltmeter
v
!
10
o
!a,l===:;:-----J
I 0
Voltmeter
Check Connector
ECU
I
VF
1./
VF
El TEl TEl
Oxygen Sensor
,
,
r-1
t - - - - - - - - -
J
' - - - - - - - - -
.----------
...---------
OXl
Sub-Oxygen Sensor
"
H
h .- _______
J
L- _ _ _ _ _ _ _
l---------~
- - - - - - - -
OX2
HT
Sub-Oxygen Sensor Heater (
+B (+Bll
CD
FI2947
El
-~
FI3383
CD
There is no voltage between ECU terminals VFl and El.
Check that there is specified voltage between ECU terminal VFl and
body ground.
NO OK
Check wiring between ECU terminal El and body ground.
OK BAD
Try another ECU.
Check for suction of air into exhaust
system.
OK
Check for air leak from air intake system.
OK
Check spark plugs.
OK
Repair or replace.
Repair air suction.
Repair air leak.
BAD , - - - - - - - - - - ,
Repair or replace.
~~
Check distributor and ignition system.
-I
Repair or replace.
L,--------~--~-~~ L_~
_ _ _ _
~
_ _ _
OK
BAD , - - - - - - - -
Check fuel pressure.
Repair or replace.
OK
~
Check injectors. -, Repair or replace.
L,-O~K~-~---------~ ~------~
Check cold start injector.
*
Repair or replace.
L,------~------~
OK
Check air flow meter.
Check operation of oxygen sensors.
BAD
Check wiring between oxygen sensors
and ECU connectors.
OK
Replace oxygen sensors.
Repair or replace.
System normal.
B~
-I
Repair wiring.
~------~
*
Rich malfunction only